Mobile device navigation applications can utilize various technologies for determining the position of the associated mobile device over time. These technologies include satellite-based technologies (e.g., GPS, Glonass, etc.), terrestrial-based technologies (e.g., based on base station or access point triangulation, etc.), and/or inertial technologies (e.g., dead reckoning based on accelerometer measurements, etc.). However, if a mobile device is inside an area such as a tunnel or underground facility (e.g., a subway station, an underground parking structure, etc.), these conventional technologies become inaccurate or unusable. For instance, satellite measurements may become unavailable or inaccurate. Measurements based on terrestrial access points may similarly become unavailable unless a sufficient number of access points are deployed within the underground facility. Further, inertial measurements are inherently imprecise and result in accumulated error over time.